Magwaza Lembe S, Bernal Antonio J B, Chope Gemma A, Alamar M Carmen, Terry Leon A
Postharvest Research Group, Cranfield University, Bedfordshire, United Kingdom.
PepsiCo International Limited, Beaumont Park, Leicester, United Kingdom.
Front Plant Sci. 2025 Jun 11;16:1595828. doi: 10.3389/fpls.2025.1595828. eCollection 2025.
The application of exogenous gases has been used to suppress sprouting in stored potato tubers. However, their efficacy in extending ecodormancy largely depends on achieving optimal gas exchange between the storage atmosphere and the tuber itself. This study aimed to investigate morphological variations and spatial distribution of lenticels and apical buds and to identify their potential role in tuber respiration rate and sprouting of five potato cultivars ('Hermes', 'Lady Claire', 'Lady Rosetta', 'Saturna', and 'VR808') during storage. Results revealed a consistent spatial pattern wherein the apical section of potato tubers exhibited significantly higher bud counts compared to lateral and stolon regions. 'Lady Claire' stood out as having the highest number of apical buds among the cultivars studied. Digital image analysis showed a seven times higher number of buds surrounding the apical eye and these were generally smaller than those distributed across the skin. 'Saturna' displayed double the lenticel density (12 lenticels cm) in smaller tubers, suggesting an inverse relationship between tuber size and lenticel density. 'Lady Claire' and 'Saturna' had respiration rates of 2.75 and 1.9 mL CO kg h, respectively, and were selected for additional respiration and ethylene efflux analyses. In both cultivars, distinct spatial differences were observed, with the apical section exhibiting a seven-fold increase in lenticel density compared to the lateral and stolon sections. Respiration rate increased five-fold when apical lenticels were blocked, whereas it decreased 30-fold when the apical was the only unblocked section, suggesting differential physiological activity across lenticel locations. The apical sections, with the highest lenticel density, exhibited elevated respiration rates as a stress-induced physiological response upon blockage, compared to the lateral and stolon sections. Lenticels changed their morphology during storage, erupting before bud movement, suggesting lenticel eruption could be used as a pre-symptomatic visual marker of dormancy break. This study highlights the critical role that lenticel morphology and spatial distribution may have in determining potato tuber gas exchange and refining allied storage regimes.
外源气体已被用于抑制贮藏马铃薯块茎的发芽。然而，它们在延长生态休眠方面的功效很大程度上取决于在贮藏环境与块茎本身之间实现最佳气体交换。本研究旨在调查五个马铃薯品种（“赫耳墨斯”、“克莱尔夫人”、“罗塞塔夫人”、“土星”和“VR808”）在贮藏期间皮孔和顶芽的形态变化及空间分布，并确定它们在块茎呼吸速率和发芽方面的潜在作用。结果显示出一种一致的空间模式，即马铃薯块茎的顶部区域与侧面和匍匐茎区域相比，芽的数量显著更多。在研究的品种中，“克莱尔夫人”的顶芽数量最多。数字图像分析表明，围绕顶眼的芽数量高出七倍，而且这些芽通常比分布在表皮上的芽更小。“土星”在较小的块茎中皮孔密度翻倍（12个皮孔/厘米），表明块茎大小与皮孔密度之间呈反比关系。“克莱尔夫人”和“土星”的呼吸速率分别为2.75和1.9毫升二氧化碳/千克·小时，并被选用于进一步的呼吸和乙烯释放分析。在这两个品种中，均观察到明显的空间差异，顶部区域的皮孔密度与侧面和匍匐茎区域相比增加了七倍。当顶部皮孔被堵塞时，呼吸速率增加了五倍，而当顶部是唯一未被堵塞的部分时，呼吸速率下降了30倍，这表明不同位置的皮孔生理活性存在差异。与侧面和匍匐茎区域相比，皮孔密度最高的顶部区域在堵塞后表现出作为应激诱导生理反应的呼吸速率升高。皮孔在贮藏期间形态发生变化，在芽移动之前就会突出，这表明皮孔突出可作为休眠打破的症状前视觉标志物。本研究强调了皮孔形态和空间分布在决定马铃薯块茎气体交换及优化相关贮藏方式方面可能具有的关键作用。
